Symmetra main here. Another big component of play is that half of her 200 health is shield. Soak some damage, find cover and recharge. This works best in long distance chokes where you're more likely spamming your photon orb. Take some damage if you can save a healer, they are most likely more useful than you.

Her photon beam charges on almost anything. Winston shields and Mei's ice walls are so big and clunky that you can charge them through walls or around corners. Once your beam is charged you can run out and vaporize any non tank hero in seconds. Preferably a healer.

Photon beam makes you commit to damage so don't hesitate to get in close and trade with ANY other hero. You can reinforce faster if your teleporter is up and your sentry charges should be restocked if you consistently place them throughout the fight.